Light-emitting device, display apparatus, and illumination apparatus

ABSTRACT

Provided is a light-emitting device that makes it possible to emit, with high efficiency, light having higher uniformity. The light-emitting device includes a light source, a wavelength conversion unit, and a wall member. The light source is disposed on a substrate. The wavelength conversion unit includes a wavelength conversion member and a transparent member that contains the wavelength conversion member therein. The wavelength conversion member is disposed to face the light source in a thickness direction and converts first wavelength light from the light source to second wavelength light. The wall member is provided on a substrate and surrounds the light source in a plane that is orthogonal to the thickness direction. A region occupied by the wavelength conversion member is wider than a region surrounded by the wall member, and entirety overlaps with the region surrounded by the wall member in the thickness direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/952,643, filed on Nov. 19, 2020, which is a continuation of U.S.patent application Ser. No. 16/084,642, filed on Sep. 13, 2018 (now U.S.Pat. No. 10,877,346, issued on Dec. 29, 2020), which application is anational phase entry under 35 U.S.C. 371 of International ApplicationNo. PCT/JP2017/002717 filed on Jan. 26, 2017, which claims priority fromJapanese Patent Application No. JP 2016-060359 filed on Mar. 24, 2016,all of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a light-emitting device, and a displayapparatus and an illumination apparatus that include the light-emittingdevice.

BACKGROUND ART

A light-emitting device using blue LEDs (Light Emitting Diode) isemployed for a backlight of a liquid crystal display apparatus or anillumination apparatus. For example, PTL 1 describes a so-called directbacklight that generates white color light through the combination of aplurality of the blue LEDs disposed on a substrate and a wavelengthconversion sheet that covers them as a whole. Further, PTL 2 discloses asurface light source that generates white color light. The surface lightsource includes, in order, a blue LED, a reflection plate, a diffusionsheet, and a phosphor layer that performs wavelength conversion, in astacked manner. In addition, PTL 3 also discloses a light-emittingdevice that performs wavelength conversion on light from alight-emitting element.

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication No.    2012-155999-   PTL 2: International Publication No. WO 2010/150516-   PTL 3: Japanese Unexamined Patent Application Publication No.    2009-140822

SUMMARY OF THE INVENTION

Incidentally, it is generally desired strongly for such a light-emittingdevice to efficiently emit light having reduced luminance unevenness,reduced color unevenness, etc. in a plane.

Therefore, it is desirable to provide a light-emitting device, and adisplay apparatus and an illumination apparatus that include thelight-emitting device, that make it possible to emit, with highefficiency, light having higher uniformity in a plane.

A light-emitting device according to an embodiment of the presentdisclosure includes a light source, a wavelength conversion unit, and awall member. The light source is disposed on a substrate. The wavelengthconversion unit is disposed to face the light source in a thicknessdirection, and includes a wavelength conversion member and a transparentmember. The wavelength conversion member converts first wavelength lightfrom the light source to second wavelength light. The transparent membercontains therein the wavelength conversion member. The wall member isprovided on a substrate and surrounds the light source in a plane thatis orthogonal to the thickness direction. Here, a region occupied by thewavelength conversion member is wider than a region surrounded by thewall member, and entirely overlaps with the region surrounded by thewall member in the thickness direction.

It is to be noted that “a wall member provided to surround each of thelight sources” is a concept that encompasses not only a shape in whichthe wall member is integrally formed without any gap to surround thelight source, but also a shape in which a slit is provided to a part ofthe wall member. The concept further encompasses a shape in which thewall member includes a plurality of parts, and the plurality of partssurround a single light source as a whole while each providing a slightgap therebetween.

Further, a display apparatus and an illumination apparatus according tothe respective embodiments of the present disclosure include theabove-described light-emitting device.

In the light-emitting device according to the embodiment of the presentdisclosure, the wavelength conversion member that is disposed to facethe light source and performs wavelength conversion is contained in thetransparent member. Therefore, it is possible to prevent the wavelengthconversion member from being exposed to the external atmosphereincluding oxygen and moisture, and thereby the degradation of thewavelength conversion member is suppressed. Further, the region occupiedby the wavelength conversion member is wider than the region surroundedby the wall member. In addition, the region occupied by the wavelengthconversion member entirely overlaps with the region surrounded by thewall member in the thickness direction. Therefore, the first wavelengthlight from the light source is mostly converted to the second wavelengthlight. This leads to the improvement of conversion efficiency.

Another light-emitting device according to an embodiment of the presentdisclosure includes a light source, a wall member, and a wavelengthconversion unit. The light source is disposed on a substrate. The wallmember is provided on the substrate and surrounds the light source in aplane that is orthogonal to a thickness direction. The wavelengthconversion unit includes a wavelength conversion member and atransparent member. The wavelength conversion member is disposed to facethe light source in the thickness direction and converts firstwavelength light from the light source to second wavelength light. Thetransparent member is placed to be directly or indirectly in contactwith the wavelength conversion member and the wall member. Here, aregion occupied by the wavelength conversion member is wider than aregion surrounded by the wall member, and entirely overlaps with theregion surrounded by the wall member in the thickness direction.

It is to be noted that “the transparent member is placed to be directlyor indirectly in contact with the wavelength conversion member and thewall member” means that another member such as an adhesive may beprovided between the wavelength conversion member and the transparentmember, and between a plurality of wall members and the transparentmember.

In another light-emitting device according to the embodiment of thepresent disclosure, the region occupied by the wavelength conversionmember is wider than the region surrounded by the wall member, andentirely overlaps with the region surrounded by the wall member in thethickness direction. Thus, the first wavelength light from the lightsource is mostly converted to the second wavelength light. Therefore,the conversion efficiency is improved. Further, the transparent memberis placed to be directly or indirectly in contact with the wavelengthconversion member and the plurality of the wall members. Therefore, highthermal dissipation is ensured, and the deterioration of the wavelengthconversion member is suppressed. Moreover, the distance between thelight source and the wavelength conversion member is made shorter,thereby improving the luminance efficiency.

According to the light-emitting devices of the embodiments of thepresent disclosure, it is possible to suppress the deterioration of thewavelength conversion member and improve the conversion efficiency.Accordingly, it is possible to efficiently emit the light having reducedluminance unevenness or reduced color unevenness in a plane. Therefore,according to the display apparatus using this light-emitting device, itis possible to achieve display performance having superior colorreproductivity, etc. Further, according to the illumination apparatususing this light-emitting device, it is possible to perform illuminationto an object with more uniformity. It is to be noted that effects of thepresent disclosure are not limited to those described above, and may beany of effects that are described in the following.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an entire configuration example of alight-emitting device according to a first embodiment of the presentdisclosure.

FIG. 2 is an enlarged perspective view of a configuration of alight-emitting section illustrated in FIG. 1 .

FIG. 3 is a cross-sectional view of a main part configuration of thelight-emitting device illustrated in FIG. 1 .

FIG. 4 is an enlarged cross-sectional view of a configuration of alight-emitting section illustrated in FIG. 3 .

FIG. 5 is a cross-sectional view of a configuration of a firstmodification example of the light-emitting section illustrated in FIG. 1.

FIG. 6 is a cross-sectional view of a configuration of a secondmodification example of the light-emitting section illustrated in FIG. 1.

FIG. 7 is a cross-sectional view of a configuration of a thirdmodification example of the light-emitting section illustrated in FIG. 1.

FIG. 8 is a cross-sectional view of a main part configuration example ofa light-emitting device according to a second embodiment of the presentdisclosure.

FIG. 9 is a perspective view of an appearance of a display apparatusaccording to a third embodiment of the present disclosure.

FIG. 10 is an exploded perspective view of a main body sectionillustrated in FIG. 9 .

FIG. 11 is an exploded perspective view of a panel module illustrated inFIG. 10 .

FIG. 12A is a perspective view of an appearance of a tablet terminalapparatus including a display apparatus of the present disclosure.

FIG. 12B is a perspective view of an appearance of another tabletterminal apparatus including the display apparatus of the presentdisclosure.

FIG. 13 is a perspective view of an appearance of a first illuminationapparatus including a light-emitting device of the present disclosure.

FIG. 14 is a perspective view of an appearance of a second illuminationapparatus including the light-emitting device of the present disclosure.

FIG. 15 is a perspective view of an appearance of a third illuminationapparatus including the light-emitting device of the present disclosure.

FIG. 16A is a characteristic diagram illustrating a chromaticitydistribution at a location directly above a wavelength conversion unitin Experimental Example 1-1.

FIG. 16B is a characteristic diagram illustrating a chromaticitydistribution at a location directly above the wavelength conversion unitin Experimental Example 1-2.

FIG. 16C is a characteristic diagram illustrating a chromaticitydistribution at a location directly above the wavelength conversion unitin Experimental Example 1-3.

FIG. 17 is a characteristic diagram illustrating, as a curved line, avariation of a chromaticity at a location directly above the wavelengthconversion unit in Experimental Examples 1-1 and 1-3.

FIG. 18A is a characteristic diagram illustrating a chromaticitydistribution of light that has passed through an optical sheet, inExperimental Example 1-1.

FIG. 18B is a characteristic diagram illustrating a chromaticitydistribution of light that has passed through the optical sheet, inExperimental Example 1-2.

FIG. 18C is a characteristic diagram illustrating a chromaticitydistribution of light that has passed through the optical sheet, inExperimental Example 1-3.

FIG. 19 is a characteristic diagram illustrating, as a curved line, avariation of a chromaticity of light that has passed through the opticalsheet, in Experimental Examples 1-1 and 1-3.

FIG. 20 is a cross-sectional view of a configuration example of alight-emitting device as a fourth modification example of the presentdisclosure.

FIG. 21 is a perspective view of a configuration example of alight-emitting section as a fifth modification example of the presentdisclosure.

MODES FOR CARRYING OUT THE INVENTION

In the following, some embodiments of the present disclosure aredescribed in detail with reference to the drawings. It is to be notedthat description is given in the following order.

1. First Embodiment and Modification Examples Thereof

An example of a light-emitting device including a wavelength conversionunit in which a wavelength conversion member is sealed inside atransparent member

2. Second Embodiment

An example of a light-emitting device in which a wavelength conversionmember is placed on a holder with a transparent member providedtherebetween

3. Third Embodiment (Display Apparatus; Liquid Crystal DisplayApparatus)

4. Application Examples of Display Apparatus

5. Application Examples of Illumination Apparatus

6. Experimental Examples

7. Other Modification Examples

1. FIRST EMBODIMENT

[Configuration of Light-Emitting Device 1]

FIG. 1 is a perspective view of an entire configuration example of alight-emitting device 1 as a first embodiment of the present disclosure.FIG. 2 is an enlarged perspective view of a light-emitting section 11 asa main part of the light-emitting device 1. FIG. 3 illustrates a crosssection taken along the line illustrated in FIG. 1 . FIG. 4 is a furtherenlarged cross-sectional view of a single light-emitting section 11. Thelight-emitting device 1 is used, for example, as a backlight thatilluminates a transmissive liquid crystal panel from behind, or as anillumination apparatus in a room, etc. As illustrated in FIG. 1 , thelight-emitting device 1 includes a plurality of light-emitting sections11 and an optical sheet 50. The plurality of light-emitting sections 11are disposed, for example, in a matrix on a substrate 10. The opticalsheet 50 is so disposed, in common to the plurality of light-emittingsections 11, as to face the plurality of light-emitting sections 11. Itis to be noted that FIG. 1 illustrates an example in which the pluralityof light-emitting sections 11 are disposed along both an X-axisdirection and a Y-axis direction that are orthogonal to each other;however, the present disclosure is not limited thereto.

In the specification, a distance direction of the substrate 10 and theoptical sheet 50 is defined as a Z-axis direction (a front-backdirection or a thickness direction). A vertical direction in a mainsurface (the widest surface) of the substrate 10 and the optical sheet50 is defined as an X direction, and a horizontal direction in the mainsurface thereof is defined as a Y direction.

(Configuration of Light-Emitting Section 11)

With reference to FIGS. 2 to 4 , description is given of a configurationof the light-emitting section 11. The plurality of light-emittingsections 11 each include a light-emitting element 12, a holder 20, and awavelength conversion unit 30. Here, the light-emitting element 12 is aspecific example that corresponds to a “light source” of the presentdisclosure. The holder 20 is a specific example that corresponds to a“wall member” of the present disclosure. The wavelength conversion unit30 is a specific example that corresponds to a “wavelength conversionunit” of the present disclosure.

The light-emitting elements 12 are disposed in a matrix on a frontsurface 10S of the substrate 10. The light-emitting element 12 is apoint light source. Specifically, the light-emitting element 12 includesan LED (Light Emitting Diode; light-emitting diode). The light-emittingelement 12 includes, for example, an optical axis CL that coincides withthe Z-axis direction. For example, the light-emitting element 12 faces aback surface 30S2 (refer to FIG. 4 ) of the wavelength conversion unit30. The light-emitting element 12 may include a package structure havinga light-emitting layer that is contained in a resin layer, or mayalternatively be a flip chip LED (light-emitting diode) having alight-emitting layer provided in an exposed manner.

The holder 20 is so provided as to surround a single light-emittingelement 12 in an XY plane that is orthogonal to the Z-axis direction, onthe front surface 10S of the substrate 10. The holder 20 forms an airlayer between the light-emitting element 12 and the wavelengthconversion unit 30. In other words, the light-emitting element 12 isprovided on the surface 10S of the substrate 10 in an opening partlocated at the middle of the holder 20. The center location in the XYplane of the holder 20 may coincide with the optical axis CL, forexample. It is to be noted that the holder 20 may have a shape in whichthe holder 20 is integrally formed without any gap to surround thelight-emitting element 12. The holder 20 may alternatively have a shapein which a slit is so provided to a part of the holder 20 as to have adiscontinued part. Further, the holder 20 may include a plurality ofparts which are separated from each other. The plurality of parts maysurround a single light-emitting element 12 as a whole while eachproviding a slight gap therebetween. Furthermore, in the presentembodiment, a single light-emitting element 12 is provided on a singlelight-emitting section 11 basis, and the holder 20 surrounds the singlelight-emitting element 12; however, the present disclosure is notlimited thereto. For example, a plurality of light-emitting elements 12may be provided to the single light-emitting section 11, and the holder20 may surround the plurality of light-emitting elements 12.

The holder 20 includes an inner wall surface 21 and a top surface 22.The inner wall surface 21 faces the light-emitting element 12. The topsurface 22 is located on side opposite to the substrate 10. The innerwall surface 21 is a reflection surface that reflects first wavelengthlight from the light-emitting element 12. The inner wall surface 21 isso inclined as to be away from the light-emitting element 12, as theinner wall surface 21 goes toward the wavelength conversion unit 30 fromthe substrate 10. Therefore, the area of a region R21U surrounded by anupper end edge 21TU of the inner wall surface 21 in the XY plane islarger than the area of a region R21B surrounded by a lower end edge21TB of the inner wall surface 21 in the XY plane. In other words, thearea of the region R21 in the XY plane, in a space surrounded by theinner wall surface 21 of the holder 20, becomes gradually larger as thearea of the region R21 goes from the substrate 10 toward the wavelengthconversion unit 30.

The holder 20 is formed, for example, by cutting-out from a plate-shapedmember, injection molding, hot press molding, or the like. A constituentmaterial of the holder 20 desirably includes a high thermally-conductivematerial having higher thermal conductivity than the thermalconductivity of the wavelength conversion unit 30, for example.Specifically, examples thereof include a metallic material including atleast one of aluminum (Al) or copper (Cu). Alternatively, as aconstituent material of the holder 20, a thermoplastic resin is alsoapplicable, in addition to the metallic material. Examples of thethermoplastic resin include a polycarbonate resin, an acrylic resin suchas PMMA (a polymethyl methacrylate resin), a polyester resin such as PET(polyethylene terephthalate), an amorphous copolymer polyester resinsuch as MS (a copolymer of methyl methacrylate and styrene), apolystyrene resin, and a polyvinyl chloride resin. Further, as in alight-emitting section 11A as a first modification example illustratedin FIG. 5 , a thin film 21F including a high reflectance material may beformed on the inner wall surface 21 of the holder 20. Examples of thehigh reflectance material include an evaporated silver film, anevaporated aluminum film, or a multilayer film-reflection film. Thismakes it possible to improve the reflectance of the inner wall surface21, and further improve the light emission efficiency of thelight-emitting device 1. It is to be noted that the high reflectancematerial refers to a material having higher reflectance than thereflectance of a transparent material 32 of the wavelength conversionunit 30, for example.

In this light-emitting device 1, the holder 20 including the inclinedinner wall surface 21 is provided. This causes the first wavelengthlight emitted from the light-emitting element 12 to be reflected againstthe inner wall surface 21, following which the first wavelength lighttravels toward the wavelength conversion unit 30. Therefore, the innerwall surface 21 of the holder 20 allows the first wavelength light thatis emitted diagonally from the light-emitting element 12 (a directioninclined with respect to the Z-axis direction) to be raised in a frontdirection (+Z direction), which leads to the contribution to theimprovement of front luminance.

It is to be noted that, in the light-emitting device 1, the dimensionW21 of the region R21U in the X-axis direction and the Y-axis directionis 3.5 mm, for example. The angle between the inner wall surface 21 andthe front surface 10S of the substrate 10 is 45°, for example. Further,the height H20 (the dimension in the Z-axis direction) of the holder 20is 0.55 mm, for example. Further, the dimension W12 of thelight-emitting element 12 in the X-axis direction and the Y-axisdirection is 1 mm, for example. The height H12 of a light-emitting pointof the light-emitting element 12 is 0.3 mm, for example.

The top surface 22 of the holder 20 is directly or indirectly in contactwith the back surface 30S2 (described later) of the wavelengthconversion unit 30. This allows the holder 20 to so function as to holdthe wavelength conversion unit 30. It is to be noted that the directcontacting of the top surface 22 of the holder 20 with the back surface30S2 of the wavelength conversion unit 30 refers to, for example, astate in which the top surface 22 is directly joined with the backsurface 30S2, through fusing, welding, or the like, without any othermember interposed therebetween. Further, the direct contacting of thetop surface 22 of the holder 20 with the back surface 30S2 of thewavelength conversion unit 30 refers to, for example, a state in whichthe top surface 22 is indirectly joined with the back surface 30S2 withanother member such as an adhesive, a pressure sensitive adhesive, orthe like, interposed therebetween.

The wavelength conversion unit 30 is disposed between the light-emittingelement 12 and the optical sheet 50 in the Z-axis direction. Thewavelength conversion unit 30 includes a wavelength conversion member 31and the transparent member 32 containing the wavelength conversionmember 31. The wavelength conversion unit 30 is so disposed as to face,in the Z-axis direction, the light-emitting element 12 surrounded by theholder 20. In other words, the wavelength conversion unit 30 is sodisposed as to cover a location directly above the light-emitting device12. The wavelength conversion unit 30 converts the wavelength of thelight (the first wavelength light) that enters the back surface 30S2from the light-emitting element 12 in the wavelength conversion member31, and outputs second wavelength light (converted light) from a frontsurface 30S1, to thereby improve coloring characteristics, for example.

The wavelength conversion member 31 includes a phosphor (fluorescentsubstance) such as fluorescent pigment, fluorescent dye, or the like, ora light-emitting substance having a wavelength converting action such asa quantum dot. The wavelength conversion member 31 is a member based onprocessing, into a sheet-shaped shape, of a resin including, forexample, a fluorescent material or a light-emitting body.

The wavelength conversion member 31 is excited by the first wavelengthlight from the light-emitting element 12. The first wavelength lightenters the back surface 31S through the back surface 30S2. Thewavelength conversion member 31 performs wavelength conversion on thefirst wavelength light under the principle of fluorescence emission,etc., to thereby output the second wavelength light from the frontsurface 31S1. The second wavelength light has a wavelength (secondwavelength) that is different from that of the first wavelength. Here,the first wavelength and the second wavelength are not particularlylimited. However, for example, in a case of a display deviceapplication, the first wavelength light may be blue color light (forexample, a wavelength ranging from about 440 nm to about 460 nm), andthe second wavelength light may be red color light (for example, awavelength ranging from about 620 nm to about 750 nm) or green colorlight (for example, a wavelength ranging from about 495 nm to about 570nm). In other words, a light-emitting element 12 is a blue color lightsource. In such a case, the wavelength conversion member 31 performswavelength conversion on the blue color light into the red color lightor the green color light.

The wavelength conversion member 31 preferably includes a quantum dot.The quantum dot is a particle having a long diameter in a range fromabout 1 nm to about 100 nm, and has a discrete energy level. An energystate of the quantum dot depends on a size thereof, and therefore, achange in the size allows for free selection of an emission wavelength.Further, emitted light of the quantum dot has a narrow spectrum width. Acolor gamut is expanded by combining light having such a steep peak.Therefore, the use of the quantum dot as a wavelength conversionmaterial allows the color gamut to be expanded with ease. Moreover, thequantum dot has high responsiveness, thus allowing for efficient use ofthe light from the light-emitting element 12. In addition, the quantumdot is high in stability as well. The quantum dot is, for example, acompound of Group 12 elements and Group 16 elements, a compound of Group13 elements and Group 16 elements, or a compound of Group 14 elementsand Group 16 elements. Examples of the quantum dot include CdSe, CdTe,ZnS, CdS, PdS, PbSe, and CdHgTe.

In the XY plane, a region R31 occupied by the wavelength conversionmember 31 is wider than the region R21U surrounded by the upper end edge21TU of the holder 20. Further, the region R31 entirely overlaps withthe region R21U surrounded by the holder 20 in the Z-axis direction(refer to FIG. 4 ). In other words, the end edge of the wavelengthconversion member 31 in the XY plane extends outside the upper end edge21TU of the holder 20. Therefore, the first wavelength light from thelight-emitting element 12 is prevented from directly entering theoptical sheet 50 not through the wavelength conversion member 31. Inother words, all of the pieces of the first wavelength light from thelight-emitting element 12 enter the wavelength conversion member 31through the transparent member 32 and are subjected to wavelengthconversion, following which the converted light travels toward theoptical sheet 50. As a result, luminance unevenness and color unevennessare sufficiently reduced.

In addition, in the light-emitting device 1, the dimension W31 of theregion R31 occupied by the wavelength conversion member 31 in the X-axisdirection and the Y-axis direction is 3 mm, for example. The dimensionW32, in the X-axis direction and the Y-axis direction, of the region R32occupied by the transparent member 32 is 3.8 mm, for example. Inaddition, the thickness H31 of the wavelength conversion member 31 is0.2 mm, for example. The thickness H32 of the transparent member 32 is0.5 mm, for example.

The transparent member 32 protects the wavelength conversion member 31by sealing the wavelength conversion member 31 so that the wavelengthconversion member 31 is not exposed to the air containing oxygen andmoisture. The transparent member 32 includes, for example, a transparentmaterial such as glass or resin. The wavelength conversion member 31serves as an active part that performs wavelength conversion on thelight from the light-emitting element 12, while the transparent member32 serves as a non-active part that allows incident light to transmittherethrough without performing wavelength conversion on the incidentlight.

The wavelength conversion unit 30 is placed on the top surface 22 of theholder 20. In other words, as described above, the back surface 30S2 ofthe wavelength conversion unit 30 (the transparent member 32) isdirectly or indirectly in contact with the top surface 22 of the holder20, which allows the wavelength conversion unit 30 to be held by theholder 20. In this light-emitting device 1, a plurality of wavelengthconversion members 31 (wavelength conversion units 30) are so providedas to be divided for each light-emitting section 11. Therefore, forexample, as compared with a single wavelength conversion sheet thatexpands over the entire surface along the front surface 10S of thesubstrate 10, the amount of materials to be used is saved, which isadvantageous in terms of cost saving and weight reduction.

Further, in the light-emitting device 1, as in a light-emitting section11B as a second modification example illustrated in FIG. 6 , forexample, a low reflection layer 33 may be so provided as to cover theback surface 30S2. The low reflection layer 33 has lower reflectancethan the reflectance of the inner wall surface 21. The first wavelengthlight that reaches the back surface 30S2 directly from thelight-emitting element 12 or that is reflected against the inner wallsurface 21 and then reaches the back surface 30S2 is less likely to bereflected against the back surface 30S2. This leads to the reduction.The first wavelength light emitted from the light-emitting element 12 ismostly subjected to wavelength conversion by the wavelength conversionmember 31.

Further, in the light-emitting device 1, as in a light-emitting section11C as a third modification example illustrated in FIG. 7 , for example,a wavelength selective reflection layer 34 may be so provided as tocover the back surface 30S2. This is because it is possible to removelight components of unnecessary wavelength regions and select desiredlight components of wavelength regions to thereby allow the selectedlight component to enter the wavelength conversion member 31.

The optical sheet 50 is disposed to face the front surface 30S1 of thewavelength conversion unit 30. The optical sheet 50 includes, forexample, a diffusion plate, a diffusion sheet, a lens film, apolarization separating sheet, etc. Providing such an optical sheet 50makes it possible to allow the light that is emitted diagonally from thelight-emitting element 12 or the wavelength conversion unit 30 to beraised in the front direction, which leads to further improvement offront luminance.

[Workings and Effects of Light-Emitting Device 1]

In the light-emitting device 1, the light-emitting element 12 of thelight-emitting section 11 is a point light source. Therefore, the firstwavelength light emitted from the light-emitting element 12 spreads inall 360-degree directions from the center of light emission of thelight-emitting element 12. The first wavelength light emitted from thelight-emitting element 12 directly enters the back surface 30S2 of thewavelength conversion unit 30 as it is, or reflected against the innerwall surface 21 of the holder 20 followed by entering the back surface30S2. The first wavelength light that has entered the wavelengthconversion unit 30 is converted to the second wavelength light by thewavelength conversion member 31, following which the converted light isoutputted from the front surface 30S1. Finally, the converted lightpasses through the optical sheet 50 and is observed as light emission.

In the light-emitting device 1 according to the present embodiment, thewavelength conversion member 31 that is disposed to face thelight-emitting element 12 and performs wavelength conversion iscontained in the transparent member 32. Therefore, it is possible toprevent the wavelength conversion member 31 from being exposed to theair including oxygen and moisture, and thereby the degradation of thewavelength conversion member 31 is suppressed. Further, the region R31occupied by the wavelength conversion member 31 is wider than the regionR21U surrounded by the holder 20. In addition, the region R31 entirelyoverlaps with the region R21U in the thickness direction. Therefore, thefirst wavelength light from the light-emitting element 12 is mostlyconverted to the second wavelength light without being leaked.Therefore, occurrence of color unevenness is suppressed, and theconversion efficiency at each light-emitting section 11 is improved.Accordingly, color unevenness and light emission efficiency for theentire light-emitting device 1 are also improved.

In the light-emitting device 1 according to the present embodiment, thewavelength conversion unit 30 is placed on the top surface 22 in such amanner to be directly or indirectly in contact with the holder 20.Therefore, heat of the wavelength conversion member 31 is absorbed bythe holder 20 through the transparent member 32, and thus, is easilydissipated to the outside. Therefore, high heat dissipation is ensured,and the deterioration of the wavelength conversion member 31 due tooverheating is suppressed. Moreover, as compared with a case where thewavelength conversion unit 30 is spaced apart from the holder 20, thedistance between the light-emitting element 12 and the wavelengthconversion member 31 becomes shorter. Therefore, the improvement ofluminance efficiency is expected.

In the light-emitting device 1 according to the present embodiment, theholder 20 has the reflection function of reflecting the first wavelengthlight from the light-emitting element 12 toward the wavelengthconversion unit 30. In addition, the holder 20 also has a holdingfunction of holding the wavelength conversion unit 30. This allows for amore compact configuration, which is advantageous in terms of sizereduction, higher integration, and lower cost reduction.

As described, according to the light-emitting device 1, it is possibleto improve the conversion efficiency while suppressing the deteriorationof the wavelength conversion member 31. Accordingly, it is possible toefficiently emit the light having reduced luminance unevenness orreduced color unevenness in a plane. Therefore, according to a displayapparatus using the light-emitting device 1, it is possible to achievedisplay performance having superior color reproductivity, etc. Further,according to an illumination apparatus using this light-emitting device1, it is possible to perform further uniform illumination to an object.

2. SECOND EMBODIMENT

[Configuration of Light-Emitting Device 2]

FIG. 8 is an enlarged cross-sectional view of a main part of alight-emitting device 2 according to a second embodiment of the presentdisclosure. The light-emitting device 2 includes a wavelength conversionunit 30A in place of the wavelength conversion unit 30. In thewavelength conversion unit 30A, the wavelength conversion member 31 isnot sealed by the transparent member 32 but is placed on a sheet-shapedor plate-shaped transparent member 35. The transparent member 35includes a front surface 35S1 and a back surface 35S2. The wavelengthconversion member 31 is placed on the front surface 35S1. The backsurface 35S2 is in contact with the top surface 22 of the holder 20directly or indirectly. The light-emitting device 2 has the similarconfiguration to that of the light-emitting device 1 according to thefirst embodiment, excluding these points.

[Workings and Effects of Light-Emitting Device 2]

In such a light-emitting device 2 as well, the region R31 occupied bythe wavelength conversion member 31 is wider than the region R21Usurrounded by the holder 20. Further, the region R31 entirely overlapswith the region R21U in the thickness direction. Therefore, the firstwavelength light from the light-emitting element 12 is mostly convertedto the second wavelength light without being leaked. Therefore,occurrence of color unevenness is suppressed, and the conversionefficiency at each light-emitting section 11 is improved. Accordingly,color unevenness and light emission efficiency for the entirelight-emitting device 2 are also improved.

In the light-emitting device 2, the wavelength conversion unit 30A isplaced on the top surface 22 in such a manner to be directly orindirectly in contact with the holder 20. Therefore, heat of thewavelength conversion member 31 is absorbed by the holder 20 through thetransparent member 35, and thus, is easily dissipated to the outside.Therefore, high heat dissipation is ensured, and the deterioration ofthe wavelength conversion member 31 due to overheating is suppressed.Moreover, as compared with a case where the wavelength conversion unit30 is spaced apart from the holder 20, the distance between thelight-emitting element 12 and the wavelength conversion member 31becomes shorter. Therefore, the improvement of luminance efficiency isexpected.

In the light-emitting device 2 according to the present embodiment, theholder 20 has the reflection function of reflecting the first wavelengthlight from the light-emitting element 12 toward the wavelengthconversion unit 30. In addition, the holder 20 also has a holdingfunction of holding the wavelength conversion unit 30. This allows for amore compact configuration, which is advantageous in terms of sizereduction, higher integration, and lower cost reduction.

Accordingly, it is expected that the light-emitting device 2 achievessimilar effects to these of the light-emitting device 1.

3. THIRD EMBODIMENT

FIG. 9 illustrates an appearance of a display apparatus 101 according toa third embodiment of the present technology. The display apparatus 101includes the light-emitting device 1, and is used as, for example, alow-profile television apparatus. The display apparatus 101 has aconfiguration in which a flat plate-shaped main body section 102 forimage display is supported by a stand 103. It is to be noted that thedisplay apparatus 101 is used as a stationary type that is placed on alevel surface such as a floor, a shelf, or a table with the stand 103attached to the main body section 102; however, the display apparatus101 may be used as a wall-mounted type with the stand 103 being detachedfrom the main body section 102.

FIG. 10 illustrates the main body section 102 illustrated in FIG. 9 inan exploded manner. The main body section 102 includes, for example, afront exterior member (bezel) 111, a panel module 112, and a rearexterior member (rear cover) 113 in this order from front side (viewerside). The front exterior member 111 is a bezel-shaped member thatcovers a front circumferential section of the panel module 112, and apair of speakers 114 are disposed on the lower side of the frontexterior member 111. The panel module 112 is fixed to the front exteriormember 111, and a power supply board 115 and a signal board 116 aremounted on the rear side of the panel module 112, and a mounting fixture117 is fixed on the rear side of the panel module 112. The mountingfixture 117 is adapted for mounting of a wall-mounting bracket, mountingof a board etc., and mounting of the stand 103. The rear exterior member113 covers a rear surface and side surfaces of the panel module 112.

FIG. 11 illustrates the panel module 112 illustrated in FIG. 10 in anexploded manner. The panel module 112 includes, for example, a frontchassis (top chassis) 121, a liquid crystal panel 122, a bezel-shapedmember (middle chassis) 123, the optical sheet 50, the light source unit1, a rear chassis (back chassis) 124, and a timing controller board 127in this order from the front side (viewer side). The light source unit 1includes a plurality of the light-emitting sections 11 arranged on thesubstrate 10.

The front chassis 121 is a bezel-shaped metallic component that covers afront circumferential section of the liquid crystal panel 122. Theliquid crystal panel 122 has, for example, a liquid crystal cell 122A, asource substrate 122B, and a flexible substrate 122C such as a COF (ChipOn Film). The flexible substrate 122C couples the liquid crystal cell122A the source substrate 122B together. The bezel-shaped member 123 isa bezel-shaped resin component that holds the liquid crystal panel 122and the optical sheet 50. The rear chassis 124 is a metallic componentof a metal such as iron (Fe), and contains the liquid crystal panel 122,the bezel-shaped member 123, and the light-emitting device 1. The timingcontroller board 127 is also mounted on the rear side of the rearchassis 124.

In the display apparatus 101, light from the light-emitting device 1 iscaused to selectively transmit by the liquid crystal panel 122 toperform image display. Here, the display apparatus 101 includes thelight-emitting device 1 having superior light emission efficiency andimproved in-plane color evenness as described in the first embodiment,resulting in enhancement of display quality of the display apparatus101.

It is to be noted that a case in which the display apparatus 101includes the light-emitting device 1 according to the first embodimenthas been described in the above-described embodiment. However, thedisplay apparatus 101 may include the light-emitting device 2 accordingto the second embodiment, in place of the light-emitting device 1.

4. APPLICATION EXAMPLES OF DISPLAY APPARATUS

Hereinafter, description is given of application examples of the displayapparatus 101 as described above to electronic apparatuses. Examples ofthe electronic apparatuses include a television apparatus, a digitalcamera, a notebook personal computer, a mobile terminal apparatus suchas a mobile phone, and a video camera. In other words, theabove-described display apparatus is applicable to electronicapparatuses in every field that display image signals inputted from theoutside or image signals generated inside as images or video pictures.

FIG. 12A illustrates an appearance of a tablet terminal apparatus towhich the display apparatus 101 according to the above-describedembodiment is applied. FIG. 12B illustrates an appearance of anothertablet terminal apparatus to which the display apparatus 101 accordingto the above-described embodiment is applied. Each of these tabletterminal apparatuses includes, for example, a display section 210 and anon-display section 220, and the display section 210 includes thedisplay apparatus 101 according to the above-described embodiment.

5. APPLICATION EXAMPLES TO ILLUMINATION APPARATUSES

Each of FIGS. 13 and 14 illustrates an appearance of a desktopillumination apparatus to which, for example, the light-emitting device1 according to the above-described embodiment is applied. For example,this illumination apparatus includes an illuminating section 843 that isattached to a supporting post 842 provided on a base mount 841, and theilluminating section 843 includes, for example, the light-emittingdevice 1. Forming, for example, the substrate 10, and the optical sheet50 in curved shapes allows the illuminating section 843 to take anyform, such as a cylindrical shape illustrated in FIG. 13 or a curvedshape illustrated in FIG. 14 .

FIG. 15 illustrates an appearance of an indoor illuminating apparatus towhich, for example, the light-emitting device 1 of the above-describedembodiment, etc., is applied. This illuminating apparatus has, forexample, illuminating sections 844 that include, for example, thelight-emitting device 1. The appropriate number of illuminating sections844 are disposed at appropriate spacing intervals on a ceiling 850A of abuilding. It is to be noted that installation locations of theilluminating sections 844 are not limited to the ceiling 850A, but theilluminating sections 844 may be installed at any location such as awall 850B or a floor (not illustrated) depending on the intended use.

In these illuminating apparatuses, illumination is performed using lightfrom, for example, the light-emitting device 1. Here, the illuminatingapparatuses each include, for example, the light-emitting device 1having superior light emission efficiency and improved in-planeluminance distribution, resulting in enhancement of illuminationquality.

6. EXPERIMENTAL EXAMPLES Experimental Examples 1-1 to 1-3

Samples of the light-emitting device 1 including the light-emittingsections 11 described in the above-described first embodiment werefabricated to compare states of color unevenness. Specifically, alight-emitting element 12 in a single light-emitting section 11 in thelight-emitting device 1 was lighted, and chromaticity distribution at alocation directly above the wavelength conversion unit 30 was measured.The results are as illustrated in FIGS. 16A, 16B, 16C, and 17 . FIGS.16A, 16B, and 16C are characteristic diagrams illustrating chromaticitydistribution in an XY plane. FIGS. 16A, 16B, and 16C respectivelycorrespond to Experimental Examples 1-1 to 1-3. In FIGS. 16A, 16B and16C, the horizontal axis represents positions in the X-axis direction,and the vertical axis represents positions in the Y-axis direction. FIG.17 is a characteristic diagram illustrating, as a curved line, avariation of chromaticity in the X-axis direction. In FIG. 17 , thehorizontal axis represents the distance (mm) from the optical axis CL inthe X-axis direction, and the vertical axis represents chromaticity.

Further, in each of the samples of the above-described light-emittingdevice 1, 25 pieces of the light-emitting sections 11 were arranged eachwith the interval of 11 mm (5 rows×5 columns), and all of thelight-emitting sections 11 were lighted to measure the chromaticitydistribution of the light that has transmitted the optical sheet 50. Theresults are illustrated in FIGS. 18A, 18B, 18C, and 19 . FIGS. 18A, 18B,and 18C are characteristic diagrams illustrating chromaticitydistribution in an XY plane. FIGS. 18A, 18B, and 18C respectivelycorrespond to Experimental Examples 1-1 to 1-3. In FIGS. 18A, 18B and18C, the horizontal axis represents positions in the X-axis direction,and the vertical axis represents positions in the Y-axis direction. FIG.19 is a characteristic diagram illustrating, as a curved line, avariation of chromaticity in the X-axis direction. In FIG. 19 , thehorizontal axis represents the distance (mm) from the optical axis CL inthe X-axis direction, and the vertical axis represents chromaticity.

Here, the dimension W31 of the wavelength conversion member 31 was setto 3.8 mm in Experimental Example 1-1, 4.0 mm in Experimental Example1-2, and 3.5 mm in Experimental Example 1-3 (refer to FIG. 4 ).Conditions other than the dimension thereof were the same inExperimental Examples 1-1 to 1-3. Specifically, the wavelengthconversion unit 30 was set to have the thickness H31 of 0.2 mm and thethickness H32 of 0.5 mm. A quantum dot was used for the wavelengthconversion member 31. Glass was used for the transparent member 32.Further, the holder 20 was set to have the dimension W21 of 3.5 mm, theheight H20 of 0.55 mm, and the angle of the inner wall surface 21 withrespect to the front surface of 10S of 30°. Further, for thelight-emitting element 12, a blue color LED package was used which hadthe dimension W12 of 1 mm and the height of a light-emitting point H12of 0.3 mm. Further, the distance OD from the front surface 10S of thesubstrate 10 to the back surface of the optical sheet 50 (the surfacefacing the light-emitting section 11) was set to 10 mm.

As illustrated in FIGS. 16C and 17 (the curved line 17C3), inExperimental Example 1-3, a state in which blue color light was leakedfrom the vicinity of the end edge of the wavelength conversion member 31was confirmed. This is presumably due to the dimension W31 of the regionR31 being the same as the dimension W21 of the region R21U. In otherwords, a reason is that a portion of the blue color light from thelight-emitting element 12 was transmitted through the transparent member32 that covered the end edge of the wavelength conversion member 31, andwas outputted from the front surface 3051 without being subjected towavelength conversion.

To the contrary, as illustrated in FIGS. 16A and 17 (the curved line17C1), in Experimental Examples 1-1 and 1-2, leakage of blue color lighteven from the vicinity of the end edge of the wavelength conversionmember 31 was not visually confirmed. This is because the dimension W31of the region R31 is larger than the dimension W21 of the region R21U,and the region R31 occupied by the wavelength conversion member 31entirely overlaps with the region R21U.

Further, as is apparent from FIGS. 18A, 18B, 18C, and 19 , the colorunevenness in the XY plane, after having caused the light to transmitthrough the optical sheet 50 including the diffusion sheet, was reducedmore in Experimental examples 1-1 and 1-2 than Experimental Example 1-3.It is to be noted that, in FIG. 19 , the curved line 19C1 corresponds toExperimental Example 1-1, and the curved line 19C3 corresponds toExperimental Example 1-3.

As described, according to the present disclosure, it was confirmed thatthe color unevenness was sufficiently reduced.

7. OTHER MODIFICATION EXAMPLES

Although description has been given of the present disclosure byreferring to the embodiments and the modification examples, the presentdisclosure is not limited thereto, and may be modified in a variety ofways. For example, the material and the thickness of each layerdescribed in the above-described embodiments are not limited thereto,and another material and thickness may be employed.

Fourth Modification Example

Further, in the above-described embodiments, etc., the wavelengthconversion unit 30 is directly or indirectly in contact with the holder20; however, as in a light-emitting device 3 as illustrated in FIG. 20 ,for example, the wavelength conversion unit 30 may be placed on atransparent member 36, and the transparent member 36 may be spaced apartfrom the top surface 22 of the holder 20.

Fifth Modification Example

Further, in the above-described embodiments, etc., the planar shape ofthe wavelength conversion unit 30, the outer rim of the holder 20, theplanar shape of the opening, etc. are formed in a square shape; however,the present technology is not limited thereto. For example, as in alight-emitting section 11D illustrated in FIG. 21 , for example, theplanar shape of the wavelength conversion unit 30, the outer rim of theholder 20, the planar shape of the opening, etc. may be formed in acircular shape. Alternatively, they may be formed in a polygonal shapesuch as hexagon, other than square. In such a case, the planar shapes ofall of the light-emitting sections in the light-emitting device may bein an identical shape, or some of them may be in a different shape.

Additionally, for example, in the above-described embodiments andmodification examples, the description has been given by specificallyreferring to configurations of the light-emitting devices 1 to 3 and thedisplay apparatus 101 (the television apparatus); however, it isunnecessary to provide all of the components, and other components maybe provided.

It is to be noted that the effects described herein are merelyillustrative and non-limiting, and may further include other effects.Further, the present technology may have the following configurations.

(1)

A light-emitting device including:

a light source disposed on a substrate;

a wavelength conversion unit that is disposed to face the light sourcein a thickness direction and includes a wavelength conversion member anda transparent member, the wavelength conversion member converting firstwavelength light from the light source to second wavelength light, thetransparent member containing therein the wavelength conversion member;and

a wall member that is provided on the substrate and surrounds the lightsource in a plane that is orthogonal to the thickness direction,

a region occupied by the wavelength conversion member being wider than aregion surrounded by the wall member, and entirely overlapping with theregion surrounded by the wall member in the thickness direction.

(2)

The light-emitting device according to (1), in which the wall member isdirectly or indirectly in contact with the wavelength conversion unit,and holds the wavelength conversion unit.

(3)

The light-emitting device according to (1) or (2), further including alight diffusion member that covers a plurality of the light sources incommon, in which

the wavelength conversion unit is disposed between the plurality oflight sources and the light diffusion member in the thickness direction.

(4)

The light-emitting device according to any one of (1) to (3), in which

the wall member includes an inner wall surface that reflects the firstwavelength light derived from the light source, and

the inner wall surface is inclined to be away from the light source, asthe inner wall surface goes toward the wavelength conversion unit fromthe substrate.

(5)

The light-emitting device according to any one of (1) to (4), in whichthe wall member includes a high thermally-conductive material havinghigher thermal conductivity than thermal conductivity of the wavelengthconversion unit.

(6)

The light-emitting device according to (5), in which the highthermally-conductive material includes at least one of aluminum orcopper.

(7)

The light-emitting device according to any one of (1) to (6), in which

the wall member includes an inner wall surface that reflects the firstwavelength light derived from the light source, and

the inner wall surface is a surface of a high reflectance material thathas a higher reflectance than a reflectance of the wavelength conversionunit.

(8)

The light-emitting device according to (7), in which the highreflectance material includes at least one of aluminum or silver.

(9)

The light-emitting device according to any one of (1) to (8), in whichthe light source is a flip chip LED (light-emitting diode).

(10)

The light-emitting device according to any one of (1) to (9), includingan air layer provided between the light source and the wavelengthconversion unit.

(11)

The light-emitting device according to any one of (1) to (10), in whichthe wavelength conversion material is a quantum dot.

(12)

The light-emitting device according to any one of (1) to (11), in which

the wall member includes an inner wall surface that reflects the firstwavelength light derived from the light source, and

a low reflection layer is provided on a light-incidence surface of thewavelength conversion unit, the light-incidence surface facing the lightsource, the low reflection layer having a lower reflectance than areflectance of the inner wall surface.

(13)

The light-emitting device according to any one of (1) to (12), in whicha wavelength selective reflection layer is provided on a light-incidencesurface of the wavelength conversion unit, the light-incidence surfacefacing the light source.

(14)

The light-emitting device according to any one of (1) to (13), in whichall of pieces of the first wavelength light from the light source enterthe wavelength conversion member via the transparent member.

(15)

A light-emitting device including:

a light source disposed on a substrate;

a wall member that is provided on the substrate and surrounds the lightsource in a plane that is orthogonal to a thickness direction; and

a wavelength conversion unit including a wavelength conversion memberand a transparent member, the wavelength conversion member beingdisposed to face the light source in the thickness direction andconverting first wavelength light from the light source to secondwavelength light, the transparent member being placed to be directly orindirectly in contact with the wavelength conversion member and the wallmember,

a region occupied by the wavelength conversion member being wider than aregion surrounded by the wall member, and entirely overlapping with theregion surrounded by the wall member in the thickness direction.

(16)

A display apparatus provided with a liquid crystal panel and alight-emitting device on rear side of the liquid crystal panel, thelight-emitting device including:

a plurality of light sources disposed on a substrate;

a plurality of wavelength conversion units that are disposed to face therespective plurality of light sources in a thickness direction and eachincluding a wavelength conversion member and a transparent member, thewavelength conversion member converting first wavelength light from theplurality of light sources to second wavelength light, the transparentmember containing therein the wavelength conversion member; and

a plurality of wall members that are provided on the substrate andsurround the respective plurality of light sources in a plane that isorthogonal to the thickness direction,

a region occupied by the wavelength conversion member being wider than aregion surrounded by the plurality of wall members, and entirelyoverlapping with the region surrounded by the wall member in thethickness direction.

(17)

An illumination apparatus provided with a light-emitting device, thelight-emitting device including:

a plurality of light sources disposed on a substrate;

a plurality of wavelength conversion units that are disposed to face therespective plurality of light sources in a thickness direction and eachincluding a wavelength conversion member and a transparent member, thewavelength conversion member converting first wavelength light from theplurality of light sources to second wavelength light, the transparentmember containing therein the wavelength conversion member; and

a plurality of wall members that are provided on the substrate andsurround the respective plurality of light sources in a plane that isorthogonal to the thickness direction,

a region occupied by the wavelength conversion member being wider than aregion surrounded by the plurality of wall members, and entirelyoverlapping with the region surrounded by the wall member in thethickness direction.

The present application is based on and claims priority from JapanesePatent Application No. 2016-60359 filed with the Japan Patent Office onMar. 24, 2016, the entire contents of which is hereby incorporated byreference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

The invention claimed is:
 1. A display device comprising, a firstexterior member holding a light-emitting device; a second exteriormember covering a back surface of the light-emitting device; and whereinthe light-emitting device comprises: a plurality of light sourcesdisposed on a substrate; a wavelength conversion unit that is disposedto face the plurality of light sources in a thickness direction andincluding a wavelength conversion member and a transparent member, thewavelength conversion member converting first wavelength light from theplurality of light sources to second wavelength light, the wavelengthconversion member comprising a quantum dot being a particle having along diameter in a range from 1 nm to 100 nm; and a plurality of wallmembers having at least one flat top surface and at least one slopedside surface connected to the flat top surface that are provided aboveon the substrate and surround the plurality of light sources in a planethat is orthogonal to the thickness direction; and wherein the firstwavelength light being blue color light and the second wavelength lightbeing red color light or green color light.
 2. The display device ofclaim 1 comprising a wavelength selective reflection layer comprising acontinuous film provided on a light-incidence surface of the wavelengthconversion unit, the light-incidence surface facing the light sources.3. The display device of claim 1, wherein regions occupied by thewavelength conversion member are wider than regions surrounded by thewall members and the regions occupied by the wavelength conversionmember entirely overlaps the regions surrounded by the wall members inthe thickness direction.
 4. The display device according to claim 1,wherein the wall members are directly in contact with the wavelengthconversion unit, and holds the wavelength conversion unit.
 5. Thedisplay device according to claim 1, further comprising a single lightdiffusion member that commonly covers a plurality of the light sources.6. The display device according to claim 5, wherein the wavelengthconversion unit is disposed between the plurality of light sources andthe light diffusion member in the thickness direction.
 7. The displaydevice according to claim 1, wherein the wall members include inner wallsurfaces that reflects the first wavelength light derived from at leastone of the plurality of light sources.
 8. The display device of claim 1,wherein the first exterior member comprises a metal.
 9. The displaydevice according to claim 1, wherein heat from the wavelength conversionmember is absorbed by the wall members through the transparent member.10. The display device according to claim 1, wherein the transparentmember protects the wavelength conversion member from moisture.
 11. Thedisplay device according to claim 1, wherein at least one of the wallmembers forms a rectangular shape.
 12. The display device according toclaim 1, wherein at least one of the wall members forms a circularshape.
 13. The display device according to claim 1, wherein the lightsources are light- emitting diodes.
 14. The display device according toclaim 1, wherein an air layer is provided between the light sources andthe wavelength conversion unit.
 15. The display device of claim 1,wherein the wavelength conversion unit is placed on top surfaces of thewall members and heat of the wavelength conversion member is absorbed bythe wall members through the transparent member.
 16. The display deviceof claim 1 comprising a liquid crystal panel over the light-emittingdevice.
 17. The display device of claim 16 comprising a wavelengthselective reflection layer comprising a continuous film provided on alight-incidence surface of the wavelength conversion unit, thelight-incidence surface facing the light sources.
 18. The display deviceof claim 1 comprising a wavelength selective reflection layer comprisinga continuous film provided on a light-incidence surface of thewavelength conversion unit, the light-incidence surface facing the lightsources.
 19. The display device of claim 1, wherein the wall members areintegrally formed without any gap surrounding the light sources.